A known system for preparing a predetermined quantity of beverage suitable for consumption using an extractable product comprises: a first exchangeable capsule, being a closed capsule, having a bottom; a first apparatus comprising a receptacle with a support surface for holding a first capsule, the first apparatus having bottom piercing means intended for piercing the bottom of the first capsule, and having a fluid dispensing device for supplying an amount of a fluid, such as water, under pressure to the first capsule.
A special class of these systems can be used for preparing the beverage using a hermetically sealed closed capsule comprising the extractable product. During beverage preparation an entrance area of such closed capsule is pierced by the bottom piercing means of the system, hence providing at least one entrance opening for supplying the fluid under pressure to the exchangeable product in the inner space of the capsule through the entrance opening. Providing the fluid under pressure to the inner space causes the pressure in the inner space of the capsule to rise. This, in turn, causes an exit area of the closed capsule to be pressed against lid piercing means present in the support surface of the receptacle. When the exit area is pressed against the lid piercing means with sufficient force, the exit area tears against the lid piercing means creating at least one exit opening through which the beverage can drain from the capsule. When using a closed capsule (a capsule that in use is pierced with the bottom piercing means of the system to enable fluid to enter the inner space of the capsule) the piercing means also enable the closed capsule, more specifically the exit area thereof, to move from the outlet of the system, more in particular to move from the support surface of the apparatus.
During preparation of the beverage, an exit area of the capsule may stick against the support surface (of the apparatus) for instance because the exit area got wet during preparation of the beverage and/or due to the fluid pressure that also presses the exit area against at least part of the support surface and/or against the lid piercing means.
Because the bottom piercing means extend through the bottom of the prior art closed capsule, the material of the bottom encloses the bottom piercing means such that when retracting the receptacle, the bottom piercing means pull the prior art closed capsule from the support surface. When the receptacle is in the retracted position, the capsule can easily leave the receptacle, for instance by falling into a waste container provided in the system.
A further, non-prepublished, system provides application of a second exchangeable capsule, being an open capsule, having a bottom comprising an entrance filter. The open capsule can be placed in the first (prior art) apparatus. However, when using the open capsule in the first apparatus (i.e. after placement), the bottom piercing means of that apparatus will not pierce the entrance filter of the open capsule. Also, the entrance filter of the open capsule is preferably already adapted to supply fluid from the fluid dispensing device to the inner space of the open capsule.
When preparing a beverage with the system using an open capsule having an entrance filter that is not pierced, the open capsule might stick to the support surface upon retraction of the receptacle. Then it may be necessary to actively remove the capsule from the receptacle, for instance with a tool, a persons fingers or any other suitable means before being able to prepare another amount of beverage after inserting a further open capsule. If the user does not notice that the open capsule is stuck against the support surface, and inserts a further capsule, the capsule may be damaged upon closing of the receptacle resulting in a beverage of a poor quality, a beverage containing extractable product or even in a damaged apparatus.
It is therefore an object of the invention to provide an improved system according to the above described type. More in particular, it is an object of the invention to provide a system for preparing a predetermined quantity of beverage wherein the risk of capsules getting stuck in the receptacle is minimized.